A serious two-car accident between a Greenfield Police cruiser and a four-door Subaru sedan at the intersection of Sanderson and High streets shortly after 8 p.m. on Sunday evening sent three people to the hospital including a police officer. October 1, 2017.Recorder Staff/Paul Franz

GREENFIELD — The Greenfield Police Department has opened an internal investigation into a fatal car crash last week involving an unnamed police officer.

“In accordance with department policy, I have ordered an internal investigation into this matter,” Police Chief Robert H. Haigh Jr. said in a statement Thursday.

Just after 8 p.m. on Oct. 1, on High Street, a Greenfield police cruiser collided with a Subaru driven by 29-year-old James Arcellana, which was crossing from Sanderson Street. Arcellana, who was first taken to nearby Baystate Franklin Medical Center and then transferred to Baystate Medical Center in Springfield, died a few days later. A passenger, who hasn’t been identified and whose current condition is unknown, also was sent to Baystate Medical Center in Springfield.

High Street’s speed limit varies between 20 and 35 miles per hour. The section of road where the accident happened, passing the hospital, is posted at 30 miles per hour for both directions of travel.

The Greenfield police officer who was in the cruiser hasn’t been named and was treated for non-life threatening injuries. The officer is still out of work, currently on “Injured on Duty Status,” Haigh said. Police vehicles often travel down High Street between the police station at 321 High St., north of the hospital, and downtown on calls.

Media inquiries about Haigh’s statement were directed to the Northwestern District Attorney’s Office, which declined to name the officer or to provide an update of the state police study of the crash, citing an ongoing investigation. Calls to Haigh for clarification on the department’s internal investigation policy were not returned at press time.

Because the crash involved local police, it remains under investigation by state police detectives assigned to the District Attorney’s Office, the State Police Collision Analysis and Reconstruction Section (“CARS”), and the State Police Crime Scene Services Section.

The cause of Arcellana’s death is being looked into by the Office of the Chief Medical Examiner.

“On behalf of the entire Greenfield Police Department, I would like to offer my condolences to the family and friends of Mr. Arcellana, and deepest thoughts to those affected by this incident. I assure all members of the community that a comprehensive and complete investigation is being done, with full cooperation of the Greenfield Police Department,” Haigh said.

Mariella Cannu, who identified as a close friend of Arcellana, said through online messaging that the Filipino immigrant was a soft-spoken and kind man. She said Arcellana was returning to New Hampshire from a New England Patriots football game in Foxborough when the accident happened.

“Out of the 10 years I’ve known James, I can’t pick out or say anything bad about him. He was such a nice guy, quiet and shy around new people but always down to do whatever and meet new people,” Cannu wrote. “He was a go-with-the-flow kind of guy, always had a smile on his face, always laughed at your jokes. I’ve never seen him mad or grumpy.”